Hepatocellular Carcinoma Confined to the Bile Duct without Hepatic Mass or Jaundice: A Case Report

Hepatocellular carcinoma (HCC) presents as a hepatic mass and may involve vascular invasion or extrahepatic spread. However, intraductal growth within the intrahepatic bile duct is rare and is often associated with obstructive jaundice. HCCs confined to the intrahepatic bile duct without detectable hepatic mass or jaundice are rare, and diagnosis is often difficult due to clinical and radiological resemblance to perihilar cholangiocarcinoma. Moreover, such cases generally carry a poor prognosis. We report a rare case of HCC that developed exclusively within the intrahepatic bile ducts, without forming a detectable mass in the liver or causing jaundice.

A 70-year-old man presented with right hypochondriac pain. Imaging revealed dilation of the intrahepatic bile ducts in the anterior sector and intraductal filling defects, particularly in the intrahepatic bile duct branch of segment 8, without a detectable hepatic mass. Alpha-fetoprotein and Duke pancreatic monoclonal antigen type 2 levels were elevated, whereas prothrombin induced by vitamin K absence-II, carbohydrate antigen 19-9, and carcinoembryonic antigen levels were within normal limits. Perihilar cholangiocarcinoma was suspected based on imaging. Right hepatectomy with extrahepatic bile duct resection was performed after preoperative portal vein embolization. Intraoperative ultrasonography and gross examination revealed no parenchymal mass. Histopathology showed atypical hepatocyte-like cell clusters with pleomorphic nuclei proliferating within the Glisson's capsule and infiltrating the adjacent liver parenchyma in a trabecular pattern without fibrous capsule formation. Tumor infiltration into the bile duct epithelium was evident. Immunohistochemical staining was positive for HepPar1 and negative for cytokeratin 19, with a 40% Ki-67 labeling index, confirming HCC diagnosis. The patient remains recurrence-free at 2 years and 7 months postoperatively.

This case highlights a rare presentation of HCC without a hepatic mass or jaundice, confined to the intrahepatic bile duct. Most patients present with obstructive jaundice. Only two other English-language cases have no prior history of primary HCC, no hepatic mass, no jaundice, and disease confined to the bile duct. Although bile duct-invading HCC is generally associated with poor prognosis, our case suggests that early surgical intervention may lead to favorable long-term outcomes in select patients.